The Snap brand silicone spray I was using on polyethelene molds worked fine. But I am out and it is evidently discontinued. Environmentally unsafe? The only thing at Home Depot was WD brand silicone spray lubricant which is kind of yellow and smells oily. I am going to take it back.
So what do all of you use? The stuff from the craft store is really expensive. Does vegetable spray give a clean shiny surface? Food grade silicon costs 2x as much as the old stuff.

Automotive department at Wallmart. Around 3.00 each, so I usually buy 2 or 3 at a time. Look for a red and white can. Lena turned me on to this one, and it works great. For the best surface, spray on and wipe off the excess.